What was the main reason due to which stagnation was seen in the colonial period in agricultural sector?

Introduction of various land revenue system.

The stagnation in the agricultural sector during British time was caused mainly because of the various systems of land settlement that were introduced by the colonial government. Particularly, under the zamindari system which was implemented in the then Bengal Presidency comprising parts of India’s present-day eastern states, the profit accruing out of the agriculture sector went to the agriculture sector went to the zamindars instead of the cultivators.